Enter a device's power, daily hours of use, and a number of days to calculate its consumption in kWh over that period.
How to Use the Energy Consumption Calculator
Enter a device's power in watts, how many hours a day it runs, and the number of days in the period you care about. Daily, monthly, and annual consumption all appear together, side by side, rather than one at a time.
There's no rate or currency field on this page, and that's deliberate rather than an oversight. Electricity prices swing wildly by country, by provider, and often by time of day — a kWh at 2pm and the same kWh at 2am can be billed at different rates under peak/off-peak plans. Attach a price to the consumption number and the result stops being comparable the moment you move it somewhere else. Leave the number in kWh and it stays meaningful everywhere.
Daily Consumption (kWh) = (Power (W) ÷ 1,000) × Hours per Day
Monthly Consumption (kWh) = Daily Consumption × Days
Annual Consumption (kWh) = Daily Consumption × 365kWh is also the currency that other tools actually want. A solar-sizing estimate, a carbon-footprint calculation, an appliance-efficiency comparison — none of them care what you happen to pay per kilowatt-hour, only how much energy is involved. Hand a consumption figure to one of those and it's immediately usable; hand it a dollar figure tied to one specific rate plan and it isn't. Once a real cost is needed for a specific rate, the site's Energy Cost Calculator picks up exactly where this one leaves off.